The PTN network refers to a packet transport network, which network is a connection oriented technology based on packet switching for uniformly transferring multi-service. The PTN network can not only preferably carry carrier-class Ethernet services, satisfy five bask properties, such as a service standardization, a high reliability, a flexible extensibility, a strict Quality of Service (QoS), an excellent Operation, Administration and Maintenance (OAM), and the like, but also support conventional Time Division Multiplexing (TDM) and Asynchronous Transfer Mode (ATM) services, and inherit management functions, such as a graphical interface of Synchronous Digital Hierarchy (SDH) network management, and an end-to-end configuration.
The PTN network is divided into three layers, which are respectively PIN Virtual Channel (VC) layer network, PTN Virtual Path (VP) layer network, and PTN Virtual Section (VC) layer network. The bottom layer of the PTN is a physical medium layer network, such as an optical fibre link. For MPLS-TP technology, the VC layer of the PTN is a Pseudo Wire (PW) layer, and the VP layer is a Label Switched Path (LSP) layer.
The PTN network possesses the OAM ability and network protection mechanism, and is mainly divided into an OAM module and a protection switching module. The OAM module is suitable for three layers of virtual section (TMS) layer/virtual channel (IMP) layer/virtual path (TMC) layer, detects fault by periodically sending an OAM message layering, notifies the protection switching module, then the protection switching module performs a master-backup switching, so as to achieve the protection for the service. The detection characteristics of the OAM module can realize a switched convergence of the service within 50 MS, and satisfy the switching performance requirement of the carrier-class Ethernet.
Light path attenuation phenomenon may be occurred in the physical medium (such as an optical fibre) carrying the service in the switching equipment carrying carrier-class Ethernet services, which may result in consecutive lost packets in the service traffic. The OAM nodule may detect such light path attenuation and report the fault to the TMS layer/TMP layer/TMC layer, and notify the protection switching module to perform protection switching of the service. The particular implementing procedure is as follows: when the link layer generates signal degrade, its physical medium port may be set to be a signal degrade status, and the signal degrade status is notified to the TMS layer, then the TMS layer reports the signal degrade status to the TMP layer via the OAM module, then the TMP layer may also report the status to the TMC layer, and the fault is reported layer by layer; and then the protection switching module sends a switching message with a status of signal degrade to achieve the protection switching of the service in the TMP layer or the TMC layer.
However, at present, the switching equipment carrying carrier-class Ethernet services can support the detection, notification and switching only when one physical port of the network-side output is in the signal degrade status.
This section provides background information related to the present disclosure which is not necessarily prior art.